JPH05126669A - Control unit with seal section breakage detecting system - Google Patents

Abstract

PURPOSE:To provide a control unit with a seal section breakage detecting system capable of quickly detecting a breakage when the breakage is generated on the seal section in the control unit while the control unit is used for a long period. CONSTITUTION:A hole 13 formed on the outer face of a control unit 1 and a leakage detecting member 14 fitted to this hole 13 are provided. The leakage detecting member 14 senses the existence of a specific fluid. The hole 13 is communicated to a void in the control unit 1, when a leakage occurs on a seal section in the control unit 1, a fluid flowing into the control unit 1 is leaked to the outside through the hole 13. The fluid leaked to the outside is brought into contact with the leakage detecting member 14 fitted in the hole 13 and sensed, and the breakage of the seal section can be detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller with a seal breakage detection mechanism, and its purpose is to leak fluid that has flowed into the controller from the flow path of the controller to the outside due to damage to the seal in the controller. The purpose of this is to provide a controller with a seal breakage detection mechanism that promptly detects this when a failure occurs.

[0002]

2. Description of the Related Art In a chemical plant, the flow rate of raw materials and fuels, the magnitude of pressure, the height of the liquid level, the temperature, etc. are measured, and appropriate measuring instruments and controllers are provided at each location in order to constantly control the values. Is provided. Flow rate in this chemical plant,
The pressure and the like are all controlled by the flow rate of the fluid, and in the current chemical industry, almost all pneumatic diaphragm control valves are used as valves used for this flow rate control.

For example, the diaphragm valve having the structure shown in FIG. 11 can be cited as an example. This diaphragm valve has a handle (a), valve stem (b), diaphragm retainer (c), diaphragm (d), valve body (e), bonnet.
(f), bonnet presser (g), spring (h), body
The main structure is (i).

In order to close the valve, when the handle (a) is turned, the valve rod (b) is lowered and the diaphragm (d) is deformed by the pressing of the valve rod (b), and the valve body (e) is springed. It descends against (h) and closes channel (j). To open the valve,
Turn the handle (a) in the opposite direction to raise the valve stem (b). Then, due to the elastic force of the spring (h), the valve body (e)
Also rises and the flow path (j) is opened, and the diaphragm
(d) also returns to its original shape when pressed by the valve body (e).

In the example of FIG. 11, the valve is in an open state, and the fluid flowing in the pipe also flows into the spring accommodating space (l) in the body (i). This fluid is normally shielded by the diaphragm (d), which is usually the seal, and does not flow out of the body (i).

However, this diaphragm (d) is fatigued due to long-term use, or foreign matter is caught during opening and closing.
If it breaks for any reason, fluid will leak from that part. Leaked fluid is bonnet (f) and bonnet retainer (g)
It leaks to the outside through the gap between the hood and the leak check hole (m) (indicated by the broken line) formed in the hood retainer (g).

Such a leak not only hinders the normal flow of fluid, but may cause a serious accident in the case of a chemical plant that handles dangerous substances such as toxic gas and flammable gas. It is a danger. Therefore, when the above-mentioned fluid leakage occurs, it is necessary to detect it promptly and replace the damaged parts, and the conventional means for detecting the fluid leakage from such a control valve is, for example, one of the plants. A method has been used in which a leakage sound detection sensor that detects a leakage sound from the control valve is attached to the part to monitor the leakage from the control valve. Alternatively, with respect to the control valve itself, measures such as a double structure of the control valve (diaphragm) were merely taken.

[0008]

However, the above-mentioned conventional technique has the following problems. When a leak sound detection sensor is installed in a part of the plant, the sensor detects the sound produced by the jet stream of fluid ejected from the gap between the valves, so that the leak sound of the leaked fluid can be detected by the sensor. If it is not spread, it will not be detected,
At the same time as the valve was damaged, there was a problem that the damaged part could not be detected early. On the other hand, when the diaphragm valve has a double structure, there is a problem in that when the diaphragm of the first stage is damaged, it is not known. Although these conventional techniques are effective means of detecting damage to the controller seal, they lack the immediacy, and therefore, in the industry, they can detect damage to the controller seal (diaphragm) in an extremely short time. Creation was desired.

[0009]

SUMMARY OF THE INVENTION The present invention is a controller with a seal part damage detection mechanism, which comprises a hole formed on the outer surface of a controller for controlling the flow rate of a fluid and a leak detection member attached to this hole. The above-mentioned conventional drawbacks are alleviated by providing a controller with a seal part damage detection mechanism characterized in that the hole communicates with a space in the controller, and the leakage detection member is sensitive to the presence of a specific fluid. Resolve.

[0010]

[Function] When the fluid leaks to the outside of the seal due to damage of the seal in the controller or the entrapment of foreign matter in the seal, and the fluid fills the void in the controller, the hole formed on the outer surface of the controller Is also filled with fluid. The presence of the fluid flowing into the hole causes the leak detecting member mounted in the hole to be sensitive.
If the leak detection member is a fluid detection sensor, this sensor detects the presence of the fluid and transmits it to the signal generator,
The signal from the signal generator can detect the damage of the seal portion. If the leak detection member is discolored by contact with a specific fluid, the breakage of the seal portion can be easily detected by visually observing the discoloration of the leak detection member.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a controller with a seal portion damage detection mechanism according to the present invention will be described below with reference to the drawings.

In FIG. 1, (1) shows a diaphragm valve which is a controller in which the present invention has been developed. This diaphragm valve (1) has a handle (2) as described in the description of the prior art.
, Valve stem (3), diaphragm retainer (4), diaphragm (5)
The main components are a valve body (6), a bonnet (7), a bonnet retainer (8), a spring (9) and a body (10). Channel
As described above, the opening and closing of (11) is performed by the vertical movement of the valve body (6) by the operation of the handle (2). O-rings (28), (29) are interposed between the body (10) and the hood retainer (8) and between the bonnet (7) and the valve rod (3). The outer surface of this diaphragm valve (1), the bonnet retainer in this example.
On the outer surface of (8), a hole (13) communicating with the space (12) in the diaphragm valve (1) is formed, and on the inner periphery of this hole (13) is a female screw (1
3a) has been formed. A leak detection member (14) is attached to the hole (13). Hereinafter, each mode of the leakage detection member (14) will be described with reference to FIGS. 2 to 10.

FIG. 2 shows a leak detecting member (14) according to the present invention.
A first embodiment of is shown. In the illustrated first embodiment, a pair of upper and lower covering bodies (15) screwed with the female screw (13a) of the hole (13) are provided, and the leakage detecting member (14) is provided in the covering body (15). Is installed. In the present invention, the leak detection member (14) is not particularly limited, and any sensor such as a sensor or a color change substance can be suitably used as long as it is sensitive to the presence of a specific fluid.

FIG. 3 shows a leak detecting member (14) according to the present invention.
A second embodiment of is shown. In the illustrated second embodiment, a fluid detection sensor is installed as a leak detection member (14) in the covering body (15), and this fluid detection sensor (14) is connected to a signal generator (16) outside the controller and an electric device. Are communicated with each other.

In the present invention, the fluid detection sensor (14) is not particularly limited as long as it is sensitive to the presence of a specific fluid. An example of this fluid detection sensor (14) is a catalytic combustion type gas sensor (141) as shown in FIG. 4, for example.

The structure of the sensor element (141a) of the catalytic combustion type gas sensor (141) is not particularly limited, and for example, a platinum wire coil (141a-2) is used as a catalyst shown in FIG. ) Is covered and baked at a high temperature of around 1000 ° C. Replace this sensor element (141a) with 3
When the platinum wire coil (141a-2) is heated to 00 to 400 ° C and an electric current is applied to it, combustion occurs due to catalytic action when fuel gas such as methane comes into contact. Therefore, the sensor element (141
a) The temperature of the internal platinum wire coil (141a-2) rises and the electric resistance increases. On the other hand, the electrical resistance of the coil does not change on the compensating element that does not carry the noble metal catalyst. Therefore, when the sensor element (141a) and the compensating element are combined, a voltage difference occurs in the electric circuit, and the fuel gas can be detected by measuring the voltage difference.

This catalytic combustion type gas sensor (141) is hardly affected by the ambient temperature and humidity, has high accuracy and is excellent in reproducibility, and therefore is suitable for use in plants such as the petrochemical industry. ..

In the present invention, as the fluid detection sensor (14), a metal oxide semiconductor type gas sensor (142) shown in FIG. 6 can be exemplified as a preferred embodiment in addition to the above-mentioned catalytic combustion type gas sensor (141).

As shown in FIG. 7, the sensor element (142a) of the metal oxide semiconductor type gas sensor (142) is a metal oxide semiconductor, particularly a tin oxide (S _n O ₂ ) sintered body (S _n O ₂ ) which is an n-type semiconductor. 142a-1) is sandwiched between a pair of platinum-based alloy wire coils (142a-2), and the circumference of the coil is covered with the same semiconductor material. A voltage is applied to one side of the coil (142a-2) so that it also functions as a heater, and the sintered body is further connected through two coils.
The Joule heat generated by passing an electric current through (142a-1) heats the sintered body (142a-1) to about 350 ° C. When the heated sintered body (142a-1) adsorbs a combustible gas such as hydrogen, alcohol, or methane, the electron concentration on the surface of the sintered body (142a-1) increases, and therefore the sintered body (142a-1) ) The resistance of itself drops sharply. Combustible gas can be detected by this change in electrical resistance.

The change in electric resistance of the tin oxide (S _n O ₂ ) sintered body (142a-1) varies depending on the temperature of the sintered body and the type of combustible gas. For example, gases that are easily oxidized, such as hydrogen, carbon monoxide, and alcohol, can be burned (1
42a-1) The sensitivity becomes maximum at the temperature, but the sensitivity becomes maximum at the temperature of the sintered body (142a-1) above 500 ° C for methane and isobutane. The same applies to the type of the sintered body. For example, zinc oxide sintered bodies other than tin oxide (SnO ₂ ) have high sensitivity to ethyl alcohol, while iron-containing large ions such as sulfate ions as impurities Sintered composite oxides of tin (eg ferric oxide (2-FeO ₃ , hematite)) show high sensitivity to propane and isobutane.
In this way, it is possible to selectively detect a specific gas component by changing the temperature of the sintered body itself or by changing the type of the sintered body.

The metal oxide semiconductor gas sensor (142) as described above is excellent in long-term stability and durability, and changes to sensitization even if it changes with time. It is suitable for the mechanism.

In addition to the catalytic combustion gas sensor (141) and the metal oxide semiconductor gas sensor (142), two electrodes (A
Known sensors such as galvanic cell type sensor (143) (see FIG. 8) composed of b), (Ac), diaphragm (B) and electrolytic solution (C) and potentiostatic electrolytic sensor are also suitable for the present invention. Used for. In addition, a potentiostatic electrolysis type sensor, an orgastat type sensor, a gas heat conduction type sensor and the like can all be suitably used.

In this second embodiment, the fluid detection sensor (14) senses the presence of the fluid filled in the gap of the controller (1) and transmits the signal to the signal generator (16), A predetermined signal is transmitted from the generator 16 (see, for example, FIG. 9). Therefore, it is possible to detect the breakage of the seal portion at a place away from the controller (diaphragm valve).

Next, a third embodiment of the seal damage detection mechanism of the controller according to the present invention will be described. In the third embodiment shown in FIG. 10, the leak detection member (14) is a fluid detection pipe (142) and is inserted into the cover (15). This fluid detector tube (1
The inside of 42) is filled with a color-changing agent (142-a) that changes color when it comes into contact with a specific fluid. This color-changing agent (142-a) is one in which a color-changing substance is coated on the surface of an inorganic carrier particle.When the color-changing substance is contacted with a specific fluid, the color-changing substance may be colored or may be decolorized to change its color. Any of them is preferably used and is not particularly limited. This discoloration occurs due to the reaction with the chemical components of the fluid or the change in pH and water content. An example of this is methyl red, bromthymol blue, or the like, which has a property of discoloring due to a change in pH. In the third embodiment, if the seal part of the controller (diaphragm valve) (1) is damaged and fluid leaks from this damaged part, the leaked fluid will cause a gap in the controller (1).
It is filled with (12) and flows into the fluid detection pipe (142) through the hole (13) formed on the outer surface of the controller (1). Fluid sensing tube
When the color change agent (142-a) in (142) comes into contact with the fluid flowing into the fluid detection tube (142), the color changes, and the color change agent changes color.
It is possible to easily detect damage to the seal portion by visually observing (142-a).

In each of the above-described embodiments, the hole (13) formed on the outer surface of the controller (diaphragm valve (1)) is used as a leak check hole in the production process before mounting the leak detection member (14). You can do this so the holes (13)
A defective product can be checked by checking whether or not the fluid is detected from the flow path (11) by allowing the fluid to flow in from. In addition, in the first and second embodiments, the leak detection sensor (14) is connected to the monitoring or alarm system by wiring so that the leak of the fluid can be promptly dealt with.

[0026]

As described above in detail, the present invention is a controller with a seal portion damage detection mechanism, which comprises a hole formed on the outer surface of a controller for controlling the flow rate of fluid and a leak detection member attached to this hole. Since the hole communicates with the void in the controller, and the leakage detecting member is sensitive to the presence of a specific fluid, the controller has a seal part damage detecting mechanism, and therefore the following effects are obtained. That is, when the fluid from the flow path of the controller flows out to the outside due to the breakage of the seal portion in the controller, the leak detection member is sensitive to the presence of the flowed-out fluid. Therefore, breakage of the seal portion in the controller can be easily and promptly detected.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a controller in which a controller with a seal portion damage detection mechanism according to the present invention is revealed.

FIG. 2 is an enlarged cross-sectional explanatory view showing an embodiment of a controller with a seal part damage detection mechanism according to the present invention.

FIG. 3 is an enlarged cross-sectional explanatory view showing an embodiment of the same.

FIG. 4 is an explanatory view of a catalytic combustion type gas sensor which is an embodiment of a fluid detection sensor which is a leakage detection member.

5 is an enlarged view of a sensor element of the catalytic combustion type gas sensor shown in FIG.

FIG. 6 is a structural explanatory view of a sensor element of a metal oxide semiconductor gas sensor which is an example of a fluid detection sensor which is a leakage detection member of a controller with a seal portion damage detection mechanism according to the present invention.

7 is an explanatory view of a sintered body of the sensor element shown in FIG.

FIG. 8 is a structural explanatory view of a galvanic battery type sensor which is an embodiment of a fluid detection sensor which is a leakage detection member of the controller with a seal portion damage detection mechanism according to the present invention.

FIG. 9 is an enlarged cross-sectional explanatory view showing an embodiment of a signal generator used in the controller with a seal part damage detection mechanism according to the present invention.

FIG. 10 is an enlarged cross-sectional explanatory view showing an embodiment of a controller with a seal part damage detection mechanism according to the present invention.

FIG. 11 is a partial cross-sectional explanatory view showing an example of a conventional controller.

[Explanation of symbols]

 1 Controller (diaphragm valve) 12 Void 13 Hole 14 Leakage detection member 15 Cover 16 Signal generator

Claims (3)

[Claims] 1. A controller with a seal part damage detection mechanism comprising a hole formed on an outer surface of a controller for controlling a flow rate of a fluid and a leak detection member attached to the hole, wherein the hole is inside the controller. A controller with a seal part breakage detection mechanism, characterized in that the leak detection member is communicated with the air gap of (1) and is sensitive to the presence of a specific fluid. 2. The fluid detection sensor, wherein the leak detection member is a fluid detection sensor, and the fluid detection sensor is mounted in a hole on the outer surface of the controller and electrically connected to a signal generator outside the controller. 2. The controller with a seal part breakage detection mechanism according to claim 1, wherein said controller is capable of detecting the presence of the fluid filled in said void in the controller and transmitting the signal to said signal generator. 3. The controller with a seal part damage detection mechanism according to claim 1, wherein the leakage detection member is discolored by contact with a specific fluid.